This invention relates to the recycling and reuse of aromatic polycarbonates.
Recycling of plastics is of increasing interest with the heightened environmental concerns currently felt. In addition, there is potential for recycle being more economical than disposal of used polymer and synthesis of new polymer to replace it.
Aromatic polycarbonates are in use in a wide variety of high volume areas. Among these are in the fabrication of transparent sheeting which may be used as a substitute for glass, and in the fabrication of optical disks used to transmit data.
Various methods for recycle of polycarbonate have been described. However, most if not all of them involve chemical reactions which degrade the polycarbonate, optimally to monomeric bisphenol which can be purified and reconverted to polycarbonate.
It would be more convenient to recycle the polycarbonate by simple purification means, which have the potential for being much cheaper than conversion to monomer and repolymerization. Moreover, since some molecular weight degradation can take place during use, it would be desirable to increase the molecular weight during recycle. Such recycle operations would be useful for both end use polycarbonate and polycarbonate recovered as drips from extruders and the like.